In North American television, this is often done on the theory that involving the audience in the plot as soon as possible will reduce the likelihood of their switching from a show during the opening commercial.
Many American series that ran from the early 1960s through the middle years of the decade (even sitcoms) adopted cold opens in later seasons.
However, beginning in the late '50s, several dramatic series, notably such Warner Bros. shows as 77 Sunset Strip, would cold-open with an attention-grabbing scene from the middle of the episode, which would repeat when the story arrived at that point.
Their use was an economical way of setting up a plot without having to introduce the regular characters, or even the series synopsis, which would typically be outlined in the title sequence itself.
British producer Lew Grade's many attempts to break into the American market meant that various shows he was involved with incorporated the cold open.
The World at War (1973–1974) is one famous exception, wherein a few short minutes an especially poignant moment is featured; after the title sequence, the events that explain the episode are outlined more fully.
Vince Gilligan has been declared "Undisputed Master of the Cold Open" in multiple reviews,[3][4] detailing particular episodes of Better Call Saul and Breaking Bad.
The Australian drama series, McLeod's Daughters used a cold open at the beginning of episodes for the majority of its run, before being phased out for its eighth and final season.
Several American children's shows use cold opens, such as Pokémon for example, uses the technique to set up the main conflict or plot of the episode.
The UFC plays a cold open before a PPV main card, to build up anticipation for the fights that will follow.
Sometimes, however, particularly for a show at the start of a new season, the actors would launch into the material without any announcement and perform a sketch written to give the audience the impression they were eavesdropping on the stars' off-microphone lives.
A memorandum was written by Gene Roddenberry on May 2, 1966, as a supplement to the Writer-Director Information Guide for the original Star Trek series, describing the format of a typical episode.